Canon PSC 2000 - Manual (Page 47)

2000 Fire Door-Fan Manual updated 2002-05-28
Page 47 of 58
Retrotec Gauge and System Calibration
All Retrotec Gauges are calibrated against a Master Reference Calibrator (MRC) that
has an accuracy of +/-0.1 Pa or 0.1 %. The concept Retrotec equipment uses is that
all of Retrotec’s products are now calibrated against the same reference. When a
blower is built, it is calibrated against the MRC for pressure and an ASTM flow
chamber for holes. A correction formula is derived for that blower to eliminate all
the error. Each gauge used in a system, is calibrated against the MRC also and
correction equations are derived that will allow for correction over the entire range.
The Retrotec software will have the correction equations for each gauge and blower
embedded in the software so all readings are corrected automatically.
For every door fan reading, three calibration corrections occur in the software;
1. the room gauge reading,
2. the flow gauge reading and
3. the blower itself.
Additional corrections:
4. Each flow pressure reading is corrected when the flow is towards the
operator to reduce the flow pressure by the room pressure to properly
reference the reading.
5. Each flow reading is corrected for temperature.
6. Barometric pressure is not corrected for because to do so would reference
the reading to local ambient conditions at the time of the test. Rather, flows
are referenced to STP conditions which are: 101,325 KPa, 50% relative
humidity and 20C. Humidity can be ignored because its effect is negligible.
Gauge calibration procedure
When the Retrotec CA2001 software is created, a calibration certificate records all
correction formula that are then used in the software. Only Retrotec can compile
these certificates but it is possible to have local instrument companies perform the
calibration. Retrotec will then take their data and create the calibration certificate
that can be emailed or mailed in a small text file. This file is imported into the
Retrotec software to allow CA2001 to perform all the corrections automatically.
The software allows the operator to select the certificate that can be used for any
particular test. Normally the operator would use the latest calibration certificate
but there are two cases where another certificate may be used:
1. Change back to an old certificate to rework or rerun old data in the form of a
new test. Old tests will retain the calibration information along with the test
so no change would have to be made unless a new test was run.
2. If different blower and/or gauge combinations were used, a different
calibration certificate can be utilized by using the “Change” button on the
Home tab. Each one of these combinations requires a separate certificate
that can be sent by Retrotec upon request.